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      <title>Kafka的生产者与消费者模型 - 交互式测验</title>
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          <div class="quiz-container">
            <div class="quiz-header">
              <h1>Kafka的生产者与消费者模型 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
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      <script>
        const quizData = [
  {
    "question": "在配置Kafka生产者以实现最高数据可靠性时，应该如何设置`acks`参数，这会带来什么主要的权衡？",
    "options": [
      "设置为 `0`，因为它不等待任何确认，可靠性最低但速度最快。",
      "设置为 `1`，因为它只需要主副本确认，是性能和可靠性的最佳平衡点。",
      "设置为 `all`，它能保证消息绝不丢失，并且对延迟没有影响。",
      "设置为 `all`，确保所有ISR（In-Sync Replicas）副本都已确认，但这会增加请求的延迟。"
    ],
    "correctAnswerIndex": 3,
    "explanation": "为了达到最高的数据可靠性，生产者应配置`acks=all`（或`-1`）。这意味着Leader副本不仅要自己写入成功，还必须等待所有ISR同步副本都确认收到消息后，才向生产者返回成功响应。这种方式最大限度地保证了消息不会丢失，但代价是等待多个副本确认会显著增加发送请求的延迟。",
    "source": "文档中「一、生产者模型优化」->「3. 数据可靠性优化」->「ACK 机制」部分",
    "hint": "文档中提到了三种 `acks` 设置，哪一种要求“所有 ISR 副本确认后返回”？"
  },
  {
    "question": "在Kafka生产者中启用幂等性 (`enable.idempotence=true`) 的主要目的是什么？",
    "options": [
      "保证跨多个分区的消息能够按顺序写入。",
      "防止因网络重试等原因导致同一条消息被重复写入分区。",
      "自动为消息启用最高级别的压缩算法以节省空间。",
      "减少生产者发送消息所需的内存缓冲区大小。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "生产者幂等性是Kafka提供的一种机制，用于确保在发生发送重试时，消息不会在目标分区中被重复存储。它通过为每个生产者分配一个唯一的PID和为每条消息分配一个序列号来实现。这对于实现“精确一次”处理语义至关重要，避免了因重试导致的数据重复问题。",
    "source": "文档中「一、生产者模型优化」->「3. 数据可靠性优化」->「幂等性支持」部分",
    "hint": "思考当生产者因为发送失败而进行“重试”时，可能会发生什么不希望看到的数据问题。"
  },
  {
    "question": "根据文档，为了确保消息被成功处理后再确认消费，从而避免消息丢失，推荐采用哪种消费者偏移量管理策略？",
    "options": [
      "开启自动提交 (`enable.auto.commit=true`)，并设置一个极短的提交间隔 `auto.commit.interval.ms`。",
      "在拉取到消息后，立即手动提交偏移量，然后再进行业务处理。",
      "关闭自动提交 (`enable.auto.commit=false`)，并在业务逻辑处理成功后手动提交偏移量。",
      "完全不管理偏移量，依赖Kafka Broker的默认机制自动处理。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "最可靠的偏移量管理方式是禁用自动提交，并在应用程序确保消息已经被完全、正确地处理之后，再调用`commitSync`或`commitAsync`方法手动提交偏移量。这样可以避免在消息处理完成前就提交了偏移量（自动提交的风险）或在处理失败后错误地提交了偏移量，从而保证了消息的“至少一次”消费。",
    "source": "文档中「二、消费者模型优化」->「2. 数据可靠性与准确性」->「偏移量管理」部分",
    "hint": "文档强调了在“消息处理成功后”再提交的重要性，哪种方式能最好地控制提交时机？"
  },
  {
    "question": "在一个消费者组中，如果消费者实例的数量超过了其订阅的主题(Topic)的分区数量，会发生什么情况？",
    "options": [
      "每个分区将由多个消费者实例共同消费，以提高处理速度。",
      "Kafka会自动为该主题增加分区数量以匹配消费者数量。",
      "部分消费者实例将会处于空闲状态，不会接收到任何消息，造成资源浪费。",
      "系统会抛出异常，导致整个消费者组停止工作。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "Kafka的分区分配原则是：在一个消费者组内，一个分区最多只能被一个消费者实例消费。因此，如果消费者实例的数量多于分区的数量，那么多出来的消费者实例将无法分配到任何分区，它们会保持空闲状态，这是一种资源的浪费。",
    "source": "文档中「二、消费者模型优化」->「1. 消费效率优化」->「并发消费」部分",
    "hint": "文档中提到“注意消费者数量不要超过分区数以避免资源浪费”。"
  },
  {
    "question": "为了显著提升Kafka生产者的吞吐量（Throughput），以下哪组参数配置的组合最为有效？",
    "options": [
      "增大 `batch.size`，启用消息压缩 (`compression.type`)，并采用异步发送。",
      "设置 `acks=all`，减小 `batch.size`，并关闭压缩。",
      "将 `linger.ms` 设置为0，并禁用异步发送。",
      "启用生产者幂等性 (`enable.idempotence=true`) 并将 `retries` 设置为0。"
    ],
    "correctAnswerIndex": 0,
    "explanation": "提升吞吐量的核心思想是减少网络请求次数和减小网络传输的数据量。增大`batch.size`可以让生产者在一次请求中发送更多消息；启用压缩可以有效减小消息体积；而异步发送则避免了请求的阻塞，极大地提升了发送效率。",
    "source": "文档中「一、生产者模型优化」->「1. 吞吐量优化」部分",
    "hint": "文档提到了三个关键点来优化吞吐量：批量、压缩和异步。"
  },
  {
    "question": "如果一个消费者在两次 `poll()` 调用之间的处理时间过长，超过了哪个参数的设定值，可能会导致其被消费者组协调器(Group Coordinator)移除，从而触发再均衡(Rebalance)？",
    "options": [
      "fetch.max.wait.ms",
      "auto.commit.interval.ms",
      "session.timeout.ms",
      "max.poll.interval.ms"
    ],
    "correctAnswerIndex": 3,
    "explanation": "`max.poll.interval.ms`参数定义了消费者在两次调用`poll()`方法之间的最大允许时间。消费者通过`poll()`方法与协调器保持心跳。如果处理一批消息的时间超过了这个阈值，协调器会认为该消费者已经“死亡”或无响应，从而将其踢出消费组，并触发一次再均衡（Rebalance），将分区重新分配给组内其他存活的消费者。",
    "source": "文档中「二、消费者模型优化」->「1. 消费效率优化」->「优化消费轮询间隔」部分",
    "hint": "文档中提到一个参数可以“提高消费效率的同时避免因超时导致的消费者被移出组”。"
  },
  {
    "question": "`linger.ms` 这个生产者参数的作用是什么？它如何帮助平衡吞吐量和延迟？",
    "options": [
      "它定义了消息在Broker上存储的最长时间。",
      "它控制了生产者在发送失败后进行重试的间隔时间。",
      "它设定了生产者在发送批次前愿意等待更多消息加入该批次的最长时间。",
      "它指定了生产者内存缓冲区的总大小，超过则阻塞发送。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "`linger.ms` 用于在吞吐量和延迟之间做出权衡。它指定了生产者在发送消息批次前，愿意等待额外消息加入批次的最长毫秒数。设置一个大于0的值（如5ms或10ms），可以让生产者有机会收集更多的消息组成一个更大的批次再发送，从而提高吞吐量，但会引入微小的延迟。如果设置为0，则消息会立即被发送，延迟最低。",
    "source": "文档中「一、生产者模型优化」->「2. 延迟优化」->「调整 linger.ms」部分",
    "hint": "该参数允许生产者在发送前“停留”或“等待”一小段时间，以期形成更大的数据批次。"
  }
];
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            nextBtn.style.display = 'block';
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            nextBtn.disabled = false; // 最后一题时，下一题按钮不禁用，而是用于显示报告
            nextBtn.textContent = (currentQuestionIndex === quizData.length - 1) ? '查看报告' : '下一题';
            
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            resultBox.className = `result-box ${isCorrect ? 'correct' : 'incorrect'}`;
            
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            html += `<div class="explanation-text">${questionData.explanation}</div>`;
            html += `<div class="source-text">来源: ${questionData.source}</div>`;
            
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                // 高亮正确答案
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        function showFinalScore() {
            document.querySelector('.quiz-body').style.display = 'none';
            document.getElementById('quiz-footer').style.display = 'none';

            const correctCount = score;
            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

            const finalScoreHtml =
                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  